St Gothard is a central point, in one of the greatest tracts of primary mountains on the face of the earth, yet arenaceous strata are found in its vicinity. Between Ayrolo and the Hospice of St Gothard, Saussure found a rock, composed of an arenaceous or granular paste, including in it hornblende and garnets. He is somewhat unwilling to give the name _gres_ to this stone, which M. Besson had done; but he nevertheless describes it as having a granulated structure.[67] [Footnote 67: Voyages aux Alpes, tom. iv. § 1822.] Among the most indurated rocks that compose the mountains of this island, many are arenaceous. Thus, on the western coast of Scotland, the great body of high and rugged mountains on the shores of Arafaig, &c. from Ardnamurchan to Glenelg, consists, in a great measure, of a granitic sandstone, in vertical beds. This stone sometimes occupies great tracts; at other times it is alternated with the micaceous, or other varieties of primary schistus; it occurs, likewise, in several of the islands, and is a fossil which we hardly find described or named by the writers on mineralogy. Much, also, of a highly indurated, but granulated quartz, is found in several places in Scotland, in beds or strata, alternated with the common schistus of the mountains. Remarkable instances of this may be seen on the north side of the ferry of Balachulish, and again on the sea-shore at Cullen. At the latter, the strata are remarkably regular, alternating with different species of schistus. At the former, the quartz is so pure, that the stone has been mistaken for marble. These examples are perhaps sufficient; but I must add, that in the micaceous and talcose schisti themselves, thin layers of sand are often found, interposed between the layers of mica or talc. I have a specimen, from the summit of one of the highest of the Grampian mountains, where the thin plates, of a talcky or asbestine substance, are separated by layers of a very fine quartzy sand, not much consolidated. The mountain from which it was brought, consists of vertical strata, much intersected by quartz veins. It is impossible to doubt, in this instance, that the thin plates of the one substance, and the small grains of the other, were deposited together at the bottom of the sea, and that they were alike produced from the degradation of rocks, more ancient than any which now exist.